chore: consolidate parallel-session WIP (HOLD — do not push)

Local snapshot of intermingled in-flight work, committed to unblock the encode
refactor (a clean ffmpeg_win.rs for the vbv-dedup follow-on). These hunks span
the same files and can't be cleanly split here; the commit bundles three
distinct workstreams that each belong in their own PR:

  - logging rework (~43 files: level re-tiering, structured fields, `?e`,
    hot-path flood latches)
  - conflicting-host detection (detect.rs + detect/{linux,windows}.rs + wiring
    in main.rs/mgmt.rs/Cargo.toml/docs/packaging)
  - standby-sink DWM-stall attribution (windows/display_events.rs + capture/
    vdisplay wiring)

NOT verified as a combination. NOT to be pushed until the refactor is done and
these are re-verified and reorganized into their proper per-workstream PRs.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

crates/punktfunk-host/src/main.rs

@@ -21,6 +21,7 @@
 mod audio;
 mod capture;
 mod config;
+mod detect;
 mod discovery;
 mod wol;
 // Goal-1 stage 6: top-level platform-only modules live under `src/linux/` and `src/windows/`; `#[path]`
@@ -31,6 +32,9 @@ mod crash;
 #[cfg(target_os = "windows")]
 #[path = "windows/ddc.rs"]
 mod ddc;
+#[cfg(target_os = "windows")]
+#[path = "windows/display_events.rs"]
+mod display_events;
 #[cfg(target_os = "linux")]
 #[path = "linux/dmabuf_fence.rs"]
 mod dmabuf_fence;
@@ -211,6 +215,19 @@ fn real_main() -> Result<()> {
             monitor_devnode::startup_recover();
             gamestream::serve(mgmt_opts, native, gamestream)
         }
+        // Report other Moonlight-compatible hosts (Sunshine/Apollo/…) installed or running on this
+        // machine — side-by-side use is unsupported. Exit 1 if any are found (so the installers and
+        // support scripts can gate on it), 0 if clean. The host also runs this at `serve` startup.
+        Some("detect-conflicts") => {
+            let found = detect::scan();
+            if found.is_empty() {
+                println!("No conflicting game-streaming host detected.");
+                Ok(())
+            } else {
+                print!("{}", detect::render_report(&found));
+                std::process::exit(1);
+            }
+        }
         // Print the management API's OpenAPI document (for client codegen).
         Some("openapi") => {
             print!("{}", mgmt::openapi_json());